Communication systems and receivers are known and advanced techniques exist for receiving and recovering symbols, which have been transmitted or sent to such receivers. Many present systems are interference limited or in many situations may be interference limited rather than noise limited. Channels over which symbols are sent are subject to various anomalies including interference and anomalies in a transmitter or receiver. Interference can include noise and adjacent channel interference as well as co-channel or on-channel interference. Adjacent channel interference is the result of transmissions on adjacent channel and results from limited adjacent channel rejection in a receiver. Co-channel interference may be the result of on channel transmissions from nearby transmitters, e.g., in geographically adjacent cells or coverage areas, and channel fading due to, e.g., Doppler shift.
Often symbol recovery in modern communication receivers utilizes channel estimation techniques. Air interface protocols often include training symbols to facilitate, e.g., channel estimation. Channel estimation is usually resource intensive and may not work particularly well in some situations, e.g., strong carrier to interference ratios. Furthermore, the number of training symbols as a percentage of total symbols is a tradeoff with payload (information bearing symbols). In many situations, e.g., rapidly varying channel characteristics, the number of training symbols may not be sufficient to provide good symbol recovery. Moreover and as known, improvements in symbol recovery error rates, generally translate into increased system capacity.